Wow @Paul.B.Rimmer, this has to be the fastest turn around time between paper and funding ever. How long was this in the works?
“We have what could be a biosignature, and a plausible story about how it got there,” Pete Worden, executive director of the nonprofit Breakthrough Initiatives, said in a statement. “The next step is to do the basic science needed to thoroughly investigate the evidence and consider how best to confirm and expand on the possibility of life.”
The Breakthrough Initiatives will help scientists take that next step, by funding a team to study the phosphine find and its potential implications in detail. The researchers will be led by MIT planetary scientist Sara Seager, an expert on exoplanet atmospheres and potential biosignatures who’s also a member of the phosphine discovery team.
“The group will investigate the scientific case for life and analyze the technical challenges of an exploratory mission in the event that such evidence proves compelling," Breakthrough Initiatives representatives said in the statement, which did not reveal how much money will be disbursed or how long the study will last.
“We are thrilled to push the envelope to try to understand what kind of life could exist in the very harsh Venus atmosphere and what further evidence for life a mission to Venus could search for,” Seager said in the same statement.
Clara Sousa-Silva, a post-doc on the author list, responded to me with a thoughtful email, and giving me permission to post it here.
Could it be we detected another molecule on Venus? Something less exciting than phosphine? Yes and no. No other known molecule with known spectra is known to absorb anywhere near the signal we detected. Emphasis on both of those knowns. There are exotic molecules for which we (as a species) simply don’t have spectra, so it is possible they could mimic the signal we detected, but finding those on Venus at ~20 ppb would still be extremely unexpected (perhaps more unexpected than simply finding phosphine).
However:
We did consider all other molecules and, even for those that have poor spectra, we usually have access to their microwave spectra. Additionally, many molecules simply do not absorb in the microwave (no permanent dipole), so could not be confused for phosphine.
We did take into account all pressure broadening and pressure shift parameters, of course. It is worth noting that the pressure shifts at the wavelengths we considered (microwave, not UV) are effectively negligible, and in particular for the temperate regions we looked at.
Bottom line: it is possible for an unknown unknown to mimic a phosphine signal, but that is extremely implausible.
In September, scientists announced they had found a chemical signature in the clouds of Venus that they said could be associated with life. However, in a new follow-up, pre-print study, the authors announced that the level of the chemical is seven times lower than they had initially reported.
Might not be a good trend in terms of science reporting… It’s become a pattern in many ways.
News reports are published claiming there are signs of life in mars, venus, the moon, pluto or whatever… and then a few months later, it turns out to be wrong.
As @swamidass said, that’s not what happened. In this case one group of scientists did claim that there are phosphines detected on Venus, and other groups of scientists disagree with them. The science journalists/news reports are not to blame here.
Ya… and the presence of phosphines was an indicator for the possibility of life if I remembered correctly.
I am not saying the news reports are dishonest. Just that there is a trend for some time wherein there are reports that life may exist in such and such plant followed by the report either being negated or nothing further coming from the discussion.
Here are some updates. There are several papers that either do not find the 1 mm signal, seen by both the James Clerk Maxwell Telescope (JCMT) and the Atacama Large Millimeter/submillimeter Array (ALMA), or do not attribute the signal to PH3. A few have been listed here, but for completeness, these are all the ones I know of:
Examines the ALMA data and finds no statistically-significant detection Snellen, I.A.G., Guzman-Ramirez, L., Hogerheijde, M.R., Hygate, A.P.S. and van der Tak, F.F.S., 2020. Re-analysis of the 267 GHz ALMA observations of Venus-No statistically significant detection of phosphine. Astronomy & Astrophysics , 644 , p.L2
Reprocesses the ALMA data and finds that the signal disappears, attributes the JCMT signal to SO2 above the clouds Villanueva, G., Cordiner, M., Irwin, P., de Pater, I., Butler, B., Gurwell, M., Milam, S., Nixon, C., Luszcz-Cook, S., Wilson, C. and Kofman, V., 2020. No phosphine in the atmosphere of Venus. arXiv preprint arXiv:2010.14305
Examines the JCMT data and finds no statistically-significant detection Thompson, M.A., 2020. The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption. Monthly Notices of the Royal Astronomical Society: Letters
In addition, one follow-up investigation into old Venus Pioneer probe data, found a signal in the clouds consistent with PH3, PH2, PH, P and PH2D:
Mogul, R., Limaye, S.S., Way, M.J. and Cordova Jr, J.A., 2020. Is Phosphine in the Mass Spectra from Venus’ Clouds?. arXiv preprint arXiv:2009.12758
We’ve replied to Villanueva et al. here:
Greaves, J.S., Richards, A., Bains, W., Rimmer, P.B., Clements, D.L., Seager, S., Petkowski, J.J., Sousa-Silva, C., Ranjan, S. and Fraser, H.J., 2020. Re-analysis of Phosphine in Venus’ Clouds. arXiv preprint arXiv:2011.08176
Where we use in-house reprocessing of the ALMA data, which significantly changes the line depth, more consistent with 1 ppb rather than 20 ppb PH3. The JCMT data remains unchanged and we argue that the feature cannot be above-cloud SO2. However, the lower abundance seen with ALMA suggests either that PH3 varies over time (something it is expected to do, given photochemical models), or that the feature is due to in-cloud SO2 (which is also known to vary with time). More observations will be needed to figure out whether the signal is really due to PH3 or due to in-cloud SO2, or some unidentified molecule.
I think there’s good reason to think that the 1 mm signal is real. We just put a reply to Snellen et al. and Thompson on arXiv, showing that both papers misapply our polynomial technique and that Snellen et al. confuse systematic and random errors. In addition, Jane applied a non-polynomial method to the JCMT data using Fourier transforms and recovered both the location and shape of the 1 mm feature. You can read the paper here: